There has been a recurring problem in maintaining the accumulated stack of documents in a vertically compact stack to which other stacks of documents may be added. In the art of conveying material, and particularly in the present case, where documents have been folded and then stacked, it is necessary to be concerned about having a clear path over the top of a stack of documents to which additional documents are to be added since any potential interference will immediately cause a jam where the new documents are added to the original stack. There is a natural tendency for documents in a stack to billow upwards, when they are supported beneath the stacks. And, documents which are folded have an even greater tendency to billow upwards in a stack. As is described in the accompanying specification, the folded documents originate from a continuous perforated web, which is typically fan folded into a supply stack, located upstream of the document conveyors.
It is absolutely essential to the operation of the document handling apparatus described herein that there be a clear, unobstructed path for the documents, or stack of documents to be processed through, especially at those locations where collation of one stack of documents must be made with one or more others. It is for this reason that the present invention has evolved and is being brought forward, as is briefly defined in the following summary.